Should You Worry? Petrol in a Diesel Car in Blackford
Provided it hasn't been started, you can worry far less than you probably are. Petrol resting in a diesel tank does nothing to your engine till something pulls it through the fuel system — the ignition priming your pump, your starter, or driving itself. So the truthful answer to the first question everyone in Blackford asks, "have I wrecked it?", is generally no. Leave your engine off then call Petrol in Diesel — that is how you keep it like that. What petrol actually does to a diesel, how to judge how far it has gone, and how to keep it from happening a second time: that is the remainder of this page.
What petrol in a diesel does to the engine
Diesel has two tasks on its way through an engine. Lubricating comes before burning; it does both. Built to very fine clearances, the injectors and the pump depend on the diesel flowing through them to stop their surfaces wearing against one another.
Of those two jobs, petrol manages the first poorly and the second not at all. Being less viscous than diesel, petrol strips away the protection a fuel system needs, leaving a pump running on that mixture to wear itself. It's also made to resist igniting under compression — the reverse of what a diesel needs — which is why you get the clattering.
Combined, those leave the shape of the trouble clear. It's movement that does the damage, not contact. Where that petrol is only inside your tank, it is an issue of fuel, nothing more. Whatever a worn pump sheds travels on, carried by the fuel, into the fuel injectors downstream, which is why a pump that has worked on the petrol is where a mechanical issue starts.
Petrol in a diesel around Blackford: how serious is it? Four situations
Fuelled but not once started — as good as it gets. At a forecourt, and genuinely only there, that petrol is still confined to that tank — since everywhere else the vehicle was driven to reach it. The task is emptying and cleaning on the spot.
Ignition on, or started for a moment. Petrol has left your tank and reached the fuel filter and the fuel lines, because the system has been bled. Still usually straightforward: drain, flush, and the fuel filter dealt with.
Driven a couple of miles. Now your pump has spent these miles working on thinned fuel. Miles is only half of it; how hard it was driven matters just as much. Either way the work runs to the tank, your lines, your filter and clean fuel through the whole circuit. The school run to the local primary school is one matter. Driving as far as Edinburgh, under 3 miles away, makes a very different job — as does any mileage on the M8, under 5 miles from Blackford, with the engine labouring hard the whole time.
Driven until it protested. Knocking, a ragged idle, smoke, a throttle that has gone soft. The engine is telling you your fuel is no longer behaving like diesel. Pull up wherever you are — the verge on Blackford Avenue, a lay-by, a side street — then leave the car there. What goes first is still the fuel drain and flush, and that deals with it, with long-term damage very unusual when a vehicle is pulled over early.
What Blackford motorists get told about petrol in a diesel — and the stories in it
Myth: "Fill it the rest of the way with diesel and it'll be fine." It will not. Topping up takes out nothing; it gives you a bigger tank of the same mixture. The assumption behind that advice — that diesel fuel systems accept petrol by percentage — is wrong.
"Newer diesels can handle a little petrol" — a myth, and closer to the opposite. Protection counts more on current diesels, not less, because their fuel passes through more precise parts at higher pressure.
"It starts, it drives, and so there is no harm" — the myth that catches most drivers than any other. The driver of a petrol engine fed diesel usually has no choice but to stop, because it will not run, and the harm stops with them. Nothing looks to have happened when a diesel fed petrol fires up, ticks over and drives away, which it usually does; meanwhile your pump grinds. Running is not the same as fine.
An old workaround for a different issue lies behind this one. Myth: "Add some two-stroke oil and drive it home." It doesn't put back what petrol has diluted, and that petrol is still inside your tank afterwards.
The next start draws petrol back round the pump out of the fuel lines and the filter, where some of that sits after your engine has run. That's why draining your tank yourself doesn't sort it — a myth. It's also truly hazardous to drain petrol into a can at the kerbside.
How does petrol in a diesel take place?
It is seldom carelessness, and nobody does it on purpose. One way only, because of the nozzles: the slimmer petrol one slips inside a diesel filler with almost no resistance, whereas the diesel one generally will not fit a petrol motor. That is how the forecourt makes it simple.
It takes place when habit and your car stop matching. A new motor, a hire car or a courtesy car. One petrol and one diesel on the driveway of the same household. A forecourt you know, but with its pumps arranged differently. Fuelling up in a rush on the way to Edinburgh Waverley, with a train to catch. Years of petrol cars behind you, a diesel Volkswagen Golf in front of you on the forecourt for its first tank — that is when. Add rain, a phone call or a back seat full of children, and your hand repeats what it has always done.
How to prevent petrol in a diesel at your next fill-up around Blackford
- Not every forecourt in the UK keeps to green for unleaded and black for diesel, even if most usually do. Check the petrol pump's label; the colour is only a hint.
- The first fill in a strange vehicle is the time to check the filler flap — on it, or on the cap, plenty of vehicles state the fuel to use.
- One of each in the household? Mark your key to the diesel — a bright fob, a sticker — since meaning to remember is not enough.
- "Diesel", aloud, before you lift the nozzle — each time a new or hired car needs its first tank. It seems daft. It does the trick.
- Thinking about something else is when this becomes an easy mistake to make, so tuck your phone away and keep your mind on the petrol pump.
- Some diesels have a filler built to refuse a petrol nozzle, and devices you can add exist for vehicles without one. Such an inhibitor helps up to a point — as a backstop, not a reason to stop reading the petrol pump.
- As soon as you realise, stop: less petrol in the tank means a weaker mixture. What to do next does not change, though — still don't start it.
Petrol already in a diesel in Blackford? Start here
In that case, there is only a short order of things. Don't start the car, and don't switch the ignition on. Still on the forecourt, at BP or anywhere else? Ask the staff to help you push the vehicle clear of the petrol pump. Phone 0333 366 0103 next, with three facts — the fuel, the approximate quantity, and whether it has run.
Corrosion and deposits are the trouble with AdBlue, where petrol means lost protection. So if it was AdBlue, say so — and read its own Blackford page.
Blackford petrol in a diesel tasks: why one costs more than another
The four situations above are four separate tasks, so no single quote for this would be fair. What moves the cost is chiefly which of them you are in. Where the car is matters too, and whether a technician can safely get to it, after the share of petrol to what that tank takes.
Ahead of any quote, not after, we ask three questions: the fuel that went in, the quantity, and if it has run. That is why. A range turns into a straight figure when those replies are in.
About Blackford itself
Blackford is a suburban area in the City of Edinburgh, situated near the River Almond and close to the city centre. Blackford sits at an elevation of around 74 metres, with the nearby Water of Leith also influencing the local landscape. Blackford is characterised by its predominantly flat-type housing, which is typical of many areas in Edinburgh. Blackford is located near other suburban areas, including West Mains and Grange Park.
Fuel drain cover across City of Edinburgh, Blackford included
The teams answering petrol in diesel calls around Blackford, in the EH postcode area, also work the places near it, West Mains, Grange Park and Newington among them. The car does not need to come to us: we drain on a forecourt, in a supermarket car park, in a lay-by or on your own drive.
Blackford: still at the petrol pump?
Nothing beats it: that is where you now are. Keep it off. Ring.